Definition of Map, linkage

Map, linkage: A map of the genes on a chromosome based
on linkage analysis. A linkage map does not show the physical distances between genes but
rather their relative positions, as determined by how often two gene loci are inherited
together. The closer two genes are (the more tightly they are linked), the more often they
will be inherited together. Linkage distance is measured in centimorgans (cM).